Update async-channel requirement from 1.5.1 to 2.1.1

Updates the requirements on [async-channel](https://github.com/smol-rs/async-channel) to permit the latest version.
- [Release notes](https://github.com/smol-rs/async-channel/releases)
- [Changelog](https://github.com/smol-rs/async-channel/blob/master/CHANGELOG.md)
- [Commits](smol-rs/async-channel@v1.5.1...v2.1.1)

---
updated-dependencies:
- dependency-name: async-channel
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

summer-boot/Cargo.toml

@@ -31,7 +31,7 @@ routefinder = "0.5.0"
 #async
 async-std = { version = "1.8.0", features = ["attributes"] }
 async-trait = "0.1.41"
-async-channel = "1.5.1"
+async-channel = "2.1.1"
 async-dup = "1.2.2"
 async-h1 = { version = "2.3.0", optional = true }